The present invention relates in general to obstetrical forceps for use in assisting in the delivery of a baby. More particularly, the present invention relates to a delivery helmet apparatus for sensing and indicating the longitudinal movement of the fetal head within the maternal birth canal.
The medical profession has been concerned with the morbidity and mortality of low birth weight infants. Since low birth weight fetuses are extremely vulnerable, two different approaches have been utilized in an attempt to minimize the traumatic consequences of spontaneous delivery. One approach has been the liberal usage of a Cesarean section. However, the use of Cesarean section delivery does not completely avoid trauma to low birth weight infants and additionally increases the rate of respiratory distress syndrome (RDS). Further, in an attempt to minimize trauma to the infant, the widening of the incision and inclusion of vertical incisions has been shown to increase the long term morbidity of the mother.
A second approach to minimize the traumatic consequences of a spontaneous delivery is to use an obstetrical forceps to assist with the delivery of the infant. Most of the obstetrical forceps are of the crossed or scissor type having cross branches or shafts with a pivot point located at an intermediate point along the shaft. The crossed forceps act as a lever and by virtue of the nature of the lever any compressive force applied to the handles is transmitted to the fetal engaging portion of the forceps and to the fetal head itself. Many infants delivered with the aid of obstetrical forceps have been clearly externally injured and possibly internally injured, although it has not been actually determined whether, and to what extent, internal injury has been caused.
Numerous obstetrical forceps have been designed and manufactured to assist in the delivery of the infant from the maternal birth canal. The previous forceps have generally been designed to substitute for maternal pushing efforts. In U.S. Pat. No. 3,665,925 to Dersookian there is described a forceps having a tension meter for indicating the amount of compressive force and tension applied to the fetal head during delivery. The Dersookian apparatus has a scale that enables the physician to observe the amount of pulling force being applied to the fetal head.
In U.S. Pat. No. 5,139,503 to Salas-Ceniceros there are disclosed obstetrical spatulas having a force indicator for displaying the force exerted on the spatulas. A handle is used to manipulate the spatulas during childbirth and the force indicator communicates the force exerted by the spatulas on the fetal head to enable the physician to adjust the pulling force applied in order to reduce or eliminate the possibility of injury.
In U.S. Pat. No. 3,785,381 to Lower and U.S. Pat. No. 3,789,849 to Laufe, there are disclosed forceps which are generally concerned with the sideways pressure applied to a fetal head. The Lower forceps include a pair of pivotally connectable blades having a pressure sensing device constructed on one of the forceps' blades. The sideways pressure exerted on the fetal head by the forceps is sensed by the sensing device and displayed on a gauge that is observable to the attending physician. When the sideways pressure received by the fetal head reaches a predetermined magnitude, the physician can reduce his hand grip on the forceps in order to correspondingly reduce the sideways pressure on the fetal head.
In Laufe there is described an obstetrical forceps that signals or indicates to the physician that a predetermined compressive force has been exceeded, and that it may be desirable to reduce the force asserted on the forceps to avoid injuring the fetal head. The Laufe forceps incorporates a shiftable blade that changes position when an external force applied to the forceps exceeds a predetermined value. An internal spring within the forceps is utilized to maintain the handle in its normal non-slipped position. However, when the compressive and traction forces exceed the spring force the handle shifts, thereby signaling the physician to reduce his hand grip and the corresponding force being applied.
Even with the variety of earlier designs of obstetrical forceps there remains a need for an improved obstetrical forceps. A need remains for an obstetrical forceps that coordinates withdrawing the forceps to correspond with the natural longitudinal movement of the fetus through the maternal birth canal. The present invention satisfies this need in a novel and unobvious way.